Polyphenyl ether treatment



United States Patent Oflice 3,409,677 Patented Nov. 5, 1968 3,409,677POLYPHENYL ETHER TREATMENT Charles P. Duncker, Brentwood, and John F.Quinn, Kirkwood, Mo., assignors to Monsanto Company, St. Louis,

Mo., a corporation of Delaware Drawing. 'Continuation-in-part ofapplication Ser. No.

300,635, Aug. 7, 1963. This application Jan. 16, 1967,

Ser. No. 609,351

5 Claims. (Cl. 260-613) ABSTRACT OF THE DISCLOSURE This inventiondescribes a oxidatlve stability of polyphenyl ethers subsequent toavailable polyphenyl ethers.

According to the present invention, the oxidative stability of apolyphenyl ether at elevated temperatures is enhanced to an unexpecteddegree by subjecting an otherwise purified and substantially neutralliquid polyphenyl ether to an anion exchange resin treatment in anonaqueous system.

It is therefore an object of this invention to provide a method forimproving the oxidative stability of polyphenyl ethers.

Other objects and advantages of this invention will become apparent byconsideration of the following specification.

Polyphenyl ethers are generally prepared by the Ullman ether synthesis,which broadly relates to ether-forming reactions, e.g., alkali metalphenoxides, such as sodium and potassium phenoxides, with aromatichalides, such as bromobenzene, in the presence of a copper catalyst,such as metallic copper, copper hydroxides or copper salts.

where n is an integer from 1 to 5.

The preferred polyphenyl ethers are those having all of their linkagesin the meta position for reasons well known. Examples of polyphenylethers contemplated herein are 3-ring ethers, such asm-diphenoxybenzene; 4-n'ng ethers, such as bis(m-phenoxybenzene) ether;S-ring ethers, such as bis(phenoxyphenoxy) benzene; 6 ring ethers, suchas bis[m (m-phenoxyphenoxy)phenyl]- ether; and the 7-ring ethers, suchas m-bis[(m-phenoxyphenoxy) phen oxy] benzene.

It is also contemplated that mixtures of such polyphenyl ethers can bestabilized by the process of this invention. For example, mixtures ofpolyphenyl ethers, in which the non-terminal phenylene rings are linkedthrough oxygen atoms in the meta or para positions, have been found tobe particularly suitable as lubricants because such mixsolidificationpoints and thus proposed, by weight, of about 65%m-bis(m-phenoxyphenoxy)benzene, 30% m-[(m-phenoxyphenoxy)(p-phenoxyphenoxy)]benzene, and 5% m-bis(p-phenoxyphenoxy)benzene.

In carrying out the present invention, the conventionally purifiedproduct obtained from the foregoing synthesis being substantiallyneutral, that is, a pH of about 7, is contacted with an anion exchangeresin prepared for a non-aqueous liquid system. Preferably, but notnecessar- It is to be noted that the liquid ethers of this invention aresubstantially neutral, that is, the synthesis products areconventionally purified to remove starting materials and side reactionproducts and thus display a pH of approximately 7.

The anion exchange resin selected is preferably a resin which resistanceto osomatic shock during the exhaustion and regeneration cycle; andpossesses a highly porous body providing a very large surface area(hereinafter referred to as a macroreticular structure).

Resins having the aforesaid properties can be prepared by formingcopolymers from monoethylenically unsatuproduct (copolymer).

The determination of suitable solvents and the amounts of monomers andsolvents required for the formation of a particular copolymer withrelatively simple to given situation. The

Specifically, a suitable macroreticular copolymer can be prepared byadmixing styrene and divinylbenzene in a suitable solvent. The amount ofdivinylbenzene can vary from about 6 to 55%, preferably from about 10 tobased on the weight of the monomer mixture. It is desirable that aminimum amount of any particular solvent be utilized in order to effectphase separation, and such amount will generally range from about to ofthe total weight of-monomer mixture and solvent. Suitable solventsinclude the alkanols having from 4 to 10 carbon atoms (e.g., n-butanol,sec-butanol, tert-amyl alcohol, n-hexanol, etc.), higher saturatedaliphatic hydrocarbons (e.g., heptane, iso-octane, etc.), and othersolvents that satisfy the aforesaid requirements.

The resin thus prepared in a cross-linked copolymer, the degree ofcross-linking varying with the polyvinylidene content, i.e., the degreeof cross-linking increases with increasing polyvinylidene content, andprovides a structure capable of having functional groups attachedthereto. Such resins have known utility as catalysts and conventionalion exchange resins in aqueous and non-aqueous systems.

It is preferred to utilize the aforesaid cross-linked copolymer withbasic functional groups attached thereto forming a base type anionexchange resin. Examples of suitable basic functional groups includehydroxy, tertiary amine, quaternary amine, and the like. The preferredmacroreticular base type anion exchange resin is one having tertiaryamine functional groups.

In order to demonstrate the unexpected oxidative stability imparted tothe polyphenyl ethers treated according to this invention, oxidationtests were conducted utilizing polyphenyl ethers prior to and subsequentto a macroreticular anion exchange resin treatment. The majorbench-scale method used for evaluating the procedure is given inMIL-L-9326A, according to which a lubricant to be tested is heated at aspecified temperature in the presence of certain metals and oxygen, andthe viscosity increase of the lubricant is determined. Additionally,information as to the corrosivity of a lubricant to metals can beobtained.

this invention, a resin bed is prepared for non-aqueous liquidoperation, and the otherwise purified polyphenyl ether is dissolved in asuitable solvent, such as toluene, and passed therethrough. Samples ofthe polyphenyl ether are taken prior to and subsequent to the resin bedtreatment. The temperature at which this resin treatment is conducted isessentially determined by the viscosity of the polyphenyl ether solutionand the temperature at which the resin is affected, generally belowabout 125 C., and preferably from about 25 C. to 50 C. The polyphenylother is then separated utilizing conventional means.

. These samples are tested according to the hereinafter described tests,and the viscosity changes are noted. Viscosity measurements were madeaccording to ASTM Method D-44553T using a Cannon-Fenske modified Ostwaldviscosimeter. The percentage of viscosity increase was determined bytaking the difference in viscosity of a composition before and after itwas heated, dividing that difference by the original viscosity, andmultiplying the quotient by 100. Thus, the oxidative stabilityimprovement factor, that is, the percentage of viscosity decreaseattributable to the resin treatment, can be readily ascertained.

Specifically, an individual 125 ml. sample of a polyphenyl ether issubjected to a temperature of 600 F. for 48 hours during which periodair is bubbled therethrough at approximately 5 liters per hour. Theviscosity of each sample after the oxidation step is compared with theviscosity of each sample prior to the oxidation step, andthe increase isnoted.

The following table sets forth the results of comparative testsperformed on 125 ml. samples of polyphenyl ethers comprising essentiallya mixture of 5-ring polyphenyl ethers having an approximate compositionof about 65% m-bis(m-phenoxyphenoxy)benzene, about 30%m-[(m-phenoxyphenoxy) (p-phenoxyphenoxy)]- benzene, and about 5%m-bis(p-phenoxyphenoxy)benzene (small amount 6-, 4- and 3-ringpolyphenyl ethers may also be present). The temperature of the resin bedand polyphenyl ether during treatment is 25 C. The volume of resinutilized is cc., and the polyphenyl ether passes therethrough atapproximately 3 ml. per minute.

Non-Ion Exchange Ion Exchange Treated Treated Improvement Factor,percent Example In Example I, the polyphenyl ether composition is asubstantially neutral mixture of the commercially prepared compounds;Example II is the same as Example I with addition of 0.1% by weight oftetraphenyl tin; and Example III is the same as Example I, but thecomposition of Example I is subjected to a digestion step with activatedalumina for from 1 to 3 hours and 0.1% by weight of tetraphenyl tin isthereafter added. Note that all the sample liquid ethers aresubstantially neutral.

Samples of the compositions of Examples I, II and III are tested forviscosity increase prior to the resin treatment. Other samples of thecompositions of Examples I, II and III are subjected to the resintreatment of this invention and thereafter tested for viscosityincrease. The results of these tests are shown in the table.

Other 3-, 4- and S-ring polyphenyl ethers and mixtures of saidpolyphenyl ethers, with or without the oxidative stabilizing additivesand/or other treatments, also display enhanced oxidative stability whensubjected to the process according to the present invention.

While this invention has been described with respect to various specificexamples and embodiments, it is understood that the invention is notlimited to such examples and embodiments, and that it can be variouslypracticed within the scope of the following claims.

What is claimed is:

1. A process which comprises contacting a substantially neutral liquidpolyphenyl ether with a macroreticular anion exchange resin in anon-aqueous system, said resin having attached thereto tertiary aminefunctional groups, for a time sufficient to improve the oxidativestability of the polyphenyl ether.

2. A process according to claim 1 wherein said polyphenyl ether is ofthe formula lD' t GiQ where n is an integer from 1 to 5.

3. A process according to claim 1 wherein said polyphenyl ether contactssaid resin at a temperature below about C.

4. A process of claim 1 wherein said polyphenyl ether is a mixture ofpolyphenyl ethers composed, by weight, of about 65%m-bis(m-phenoxyphenoxy)benzene, 30% m- (m-phenoxyphenoxy)(p-phenoxyphenoxy) ]benzene, and 5% m-bis(p-phenoxyphenoxy)benzene.

5. A process of claim 1 wherein said macroreticular resin is across-linked styrene-polyvinylidene copolymer anion exchange resinhaving tertiary amine functional groups attached thereto and saidpolyphenyl ether contacts said resin at a temperature from about 25 to50 C.

(References on following page) 6 References Cited OTHER REFERENCES vUNITED STATES PATENTS j I Heftrnann: Chromatography, published byReinhold 2 i60'91'1 6(1939 'kiiss11 v 252 393 X Publishing Corp., NewYork, 1961, pp. 34 35, 278-279, 2,211,55 8/1940 Colifi et a1.:, ;25i f19.71 5 and most pfrtment- I v u IEIIHII; 6t 211.1 IOIl RCSlnS, P. 38,II'lQSt permen.

FOREIGN PATENTS 1 1. 886,978 1/1962 Gi'eaf'Bri'taiii. PATRICKP- V xminer.

